The goal of the project is to reduce the frequency and severity of flooding and to protect human life and property in the communities of Ross and Kentfield by enhancing and improving features of Corte Madera Creek.
The project will make improvements to the concrete channel that the U.S. Army Corps of Engineers (USACE) built in the 1960-70s. The project area starts upstream at Lagunitas Road in the Town of Ross and ends downstream at the earthen channel in Kentfield. The project area is divided into three units, based on the original USACE concrete channel project units:
View the EIR maps of the Project elements within Units 2, 3 and 4.
The proposed channel improvements provide increased flood risk reduction (to a 25-year flooding level event) for residents and businesses within the Town of Ross and Kentfield. The project will also improve fish passage and habitat.
The project includes these activities:
- Remove a fish ladder and lower the channel within Unit 4 to remove an impediment to flood flow
- Create taller and/or new floodwalls in Units 2 and 3 to control flood flows
- Add a stormwater pump station to control flooding in the Granton Park neighborhood
- Create larger fish resting pools within the concrete channel in Unit 3 to improve fish passage
- Remove portions of the concrete channel from Stadium Way downstream to the natural earthen channel to improve fish and wildlife habitat
Timeline
- August 17, 2021: Environmental impact report certified by the Marin County Board of Supervisors, with the Frederick Allen Park project component removed from the project.
- Fall 2022 - Winter 2026: Project Construction
- 2022-2024: Construction of new vehicular maintenance access ramp and Granton Park stormwater pump station completed.
- Anticipated in 2025:
- Remove the Lower College of Marin concrete walls and restore wetlands.
- Anticipated in 2026:
- Improve fish resting pools along bottom of concrete channel.
- Remove Unit 4- fish ladder and transition to natural earthen channel upstream.
- Raise sections of existing Unit 2 & 3 concrete channel walls.
- Ongoing:
- Coordination with FEMA on assessments of hydraulic modeling. Related compliance with state and federal regulations that are applicable.
Funding
The overall project cost estimate is approximately $18 million, which includes design, EIR, CEQA, permitting, real estate, project management, grant management, construction management, construction work, revegetation, and monitoring. Of the approximate $18 million, the construction phase alone is estimated at approximately $12 million.
Funding sources include:
- California Department of Water Resources
- State Coastal Conservancy
- County Sea Level Rise Funds from American Rescue Plan Act
- US Fish & Wildlife Service National Coastal Wetlands Conservation Grant
- Ross Valley Flood Control Zone 9 Storm Drainage Fee
- Other future grant funding sources
Zone
Zone 9: Ross Valley
